Glass sheets are conventionally formed by heating on a heating conveyor within a furnace until being sufficiently hot for deformation. The heated glass sheets are then transferred to a mold for forming either solely by that mold or in cooperation with one or more additional molds. U.S. Pat. No. 4,578,103 Fackelman and U.S. Pat. No. 4,615,724 Fackelman disclose a topside transfer platen that allows transfer of a heated glass sheet from a heating conveyor to a mold without any direct contact during the transfer. More specifically, the glass sheets are heated on a roll conveyor and then conveyed to the topside transfer platen which includes a downwardly facing surface having a first set of holes through which a vacuum is drawn and a second set of holes through which pressurized gas is supplied such that the glass sheet is supported without any direct contact with the topside transfer platen. As such, there is no possibility of scratching, marring or otherwise disfiguring the glass sheet surfaces during the transfer.
The inventions of the two Fackelman patents involve different structure and operation. In the U.S. Pat. No. 4,578,103 Fackelman patent, the topside transfer platen is fixedly mounted and the heating conveyor is a roll conveyor that is specifically disclosed as not overlapping the topside transfer platen since it was then thought that any overlap would result in obstruction problems with the transfer. In the U.S. Pat. No. 4,615,724 Fackelman patent, the topside transfer platen is movable upwardly and downwardly above the heating conveyor to permit a mold to move under the raised topside transfer platen with a heated glass sheet supported thereby so that the release of the vacuum would then provide the transfer to the mold for subsequent movement and cooling of the glass sheet. Both of these Fackelman patents disclose the topside transfer platen as being made of a refractory block including passages for respectively communicating the first and second sets of holes with sources of vacuum and pressurized gas to provide the support of the hot glass sheets without any direct contact.
Since the initial Fackelman inventions, topside transfer platens for handling hot glass sheets as described above have been made from fabricated metal capable of withstanding high temperatures, usually stainless steel, as disclosed by U.S. Pat. No. 5,002,599 McMaster et al. Also, positioners have been developed for positioning hot glass sheets while suspended from topside transfer platens as disclosed by U.S. Pat. No. 5,066,321 Kramer et al., U.S. Pat. No. 5,669,953 Schnabel, Jr. et al., and U.S. Pat. No. 5,902,366 Schnabel, Jr. et al.